Carbon nanofiber-based hydrodesulfurization catalyst with molybdenum oxide and cobalt oxide

Abstract

Carbon nanofiber doped alumina (Al—CNF) supported MoCo catalysts in hydrodesulfurization (HDS), and/or boron doping, e.g., up to 5 wt % of total catalyst weight, can improve catalytic efficiency. Al—CNF-supported MoCo catalysts, (Al—CNF—MoCo), can reduce the sulfur concentration in fuel, esp. liquid fuel, to below the required limit in a 6 h reaction time. Thus, Al—CNF—MoCo has a higher catalytic activity than Al-MoCo, which may be explained by higher mesoporous surface area and better dispersion of MoCo metals on the AlCNF support relative to alumina support. The BET surface area of Al-MoCo may be 75% less than Al—CNF—MoCo, e.g., 166 vs. 200 m2/g. SEM images indicate that the catalyst nanoparticles can be evenly distributed on the surface of the CNF. The surface area of the AlMoCoB5% may be 206 m2/g, which is higher than AlMoCoB0% and AlMoCoB2%, and AlMoCoB5% has the highest HDS activity, removing more than 98% sulfur and below allowed levels.

The invention claimed is: 
     
       1. A hydrodesulfurization catalyst, comprising:
 catalytic material comprising a molybdenum oxide and a cobalt oxide; and 
 a catalyst support comprising alumina; and 
 wherein the hydrodesulfurization catalyst support further comprises carbon nanofibers dispersed on a surface of the alumina; and 
 wherein the hydrodesulfurization catalyst further comprises a dopant comprising boron in an amount such that the boron is present in a range of from 1 to 5.5 wt. % relative to total hydrodesulfurization catalyst weight, 
 wherein the catalytic material is homogenously dispersed on the catalyst support. 
 
     
     
       2. The hydrodesulfurization catalyst of  claim 1 , wherein the catalytic material comprises 12 to 18 wt. % of molybdenum, relative to total hydrodesulfurization catalyst weight. 
     
     
       3. The hydrodesulfurization catalyst of  claim 1 , wherein the catalytic material comprises 3 to 8 wt. % of cobalt, relative to total hydrodesulfurization catalyst weight. 
     
     
       4. The hydrodesulfurization catalyst of  claim 3 , wherein the molybdenum and/or cobalt is present in the form of nanoparticles. 
     
     
       5. The hydrodesulfurization catalyst of  claim 1 , having a BET surface area in a range of 150 to 230 m 2 /g. 
     
     
       6. The hydrodesulfurization catalyst of  claim 1 , wherein the carbon nanofibers have an average diameter of 20 to 40 μm. 
     
     
       7. The hydrodesulfurization catalyst of  claim 1 , having a meso-pore surface area in a range of from 165 to 185 m 2 /g. 
     
     
       8. The hydrodesulfurization catalyst of  claim 1 , having a total pore volume in a range of from 0.3 to 0.33 cm 3 /g. 
     
     
       9. The hydrodesulfurization catalyst of  claim 1 , having an average pore diameter in a range of from 5 to 7 nm. 
     
     
       10. The hydrodesulfurization catalyst of  claim 1 , wherein the catalytic material comprises no more than 5 wt. % of sulfur.